SELF-SIMILAR CHARACTER OF THE PROPAGATION OF A DENSITY FRONT IN A SHALLOW WATER BODY.

Currents caused by differences in the density of contacting water masses occur during discharge of warm waters by electric power stations and industrial enterprises, penetration of sea water as a salt wedge into river estuaries, and in a number of other cases. Such currents are often called density (gravity) currents, or intrusions. The problem of the propagation velocity of the intrusion front is important for applications. Many characteristics of density currents substantially depend on the value of the densitometric Froude number Fr or, what is equivalent, the global Richardson number Ri. When Fr approximately equals 1 an important role in the balance of the driving forces is played by inertial forces, and when Fr VM LS TH 1 by viscous forces.